1. Field of the Invention
This invention relates in general to hot surface ignitors used in gas furnaces having burner boxes and, in particular, to a snap-in bracket for receiving the hot surface ignitor and positioning it relative to the burner box of the furnace.
2. Discussion of the Prior Art
The residential heating industry has benefitted from the advent of hot surface ignitors. Such ignitors are used in gas furnaces to ignite the gas as it exits combustion burners provided in a burner box. The hot surface ignitors are an advancement over the lit gas pilot lights used in older furnaces to ignite the primary flow of gas for heating.
Hot surface ignitors typically include a silicon oxide resistance portion cemented in a ceramic base. Electric wires are connected to the ceramic base to provide electric current to the silicon oxide resistance portion. Current supplied to the resistance portion is converted to heat that produces a red hot glow in the silicon oxide. In this condition, the hot surface ignitor is enabled to ignite the gas exiting the combustion burners.
In typical gas furnaces, gas is supplied to the furnace by a gas manifold. The manifold is provided with jets that direct the gas into burners contained in a burner box. The gas is ignited as it exits the burners contained in the burner box. The heated flue gas produced by combustion of the gas is then directed into a heat exchanger. The heated flue gas is induced to move through the heat exchanger while a blower moves clean circulating air over the heat exchanger. The heated air thus produced is directed to desired locations by a system of ducts and registers.
Prior gas furnaces utilizing hot surface ignitors secure the ignitor within the burner box by means of a sheet metal screw. A hole would be provided through the ceramic base of the igniter to receive the screw. During installation of the ignitor in the burner box, this mounting screw could be tightened to the point of creating crack-inducing stresses within the ceramic base portion of the ignitor. In addition, this method of installation resulted in exposing the entire ceramic base and electric supply wires to the relatively high temperatures maintained within the burner box during combustion.